A vertically arranged two lamp lighting apparatus for vehicles having a high beam lamp and a low beam lamp has conventionally been known (see, for example, Japanese Patent No. 3447451). Such a lighting apparatus is constructed as follows. Specifically, a lens body having a lens corresponding to either a high-beam lamp or a low-beam lamp is mounted to a housing main body to form a lamp housing. An individual bulb and an individual reflector are disposed in the lamp housing and the high-beam lamp and low-beam lamp are fitted in a vertical row arrangement. The conventional lighting apparatus thereby reduces the number of parts used as compared with a structure having a separate lamp housing for each of the two different types of lamps (high-beam and low-beam).
As such, a vehicle lighting apparatus may be constructed by forming a lamp housing by mounting a lens body, including a lens, to a housing main body and disposing a bulb and the like in the lamp housing to form a lamp. To prevent a lens inner surface from being fogged due to moisture in the lamp housing evaporating, a typical vehicle lighting apparatus includes an air vent hole disposed in the lamp housing and an air vent pipe connected to the air vent hole on an outside. (See, for example, Japanese Patent No. 3335228.)
In the former structure cited above, however, a single lens body forms the lens corresponding to each of the two different types of lamps (high-beam and low-beam). However, this particular configuration hampers emphasizing the shape of each individual lens and the shape of each individual lamp. Thus, it is difficult to enhance a degree of freedom in designing such a lighting apparatus.
For example, an enhanced degree of freedom is enhanced by a reflector headlight including a multi reflector having a plurality of cut surfaces for light distribution formed on a reflection surface thereof, and a clear lens which has not undergone lens cutting. In such a headlight, brightness of the reflector surface is emphasized and therefore an enhanced degree of freedom in design is provided.
Fog on the inner surface of such a lens is relatively easy to notice. Therefore, it is important in a lamp combining a multi reflector with a clear lens, to ensure good ventilation performance in areas near the inner surface of the lens.
However, in an effort to ensure good ventilation, enlarging the air vent hole or increasing the number of the air vent holes, makes it difficult to design the air vent hole. Similarly, making the air vent pipe project outside the lamp housing contributes to a complicated housing structure.